Liquids & Solids Changes of State

Phase Changes

Phase Changes Evaporation molecules at the surface gain enough energy to overcome IMF Volatility measure of evaporation rate depends on temp & IMF

Phase Changes temp volatility IMF volatility Boltzmann Distribution # of Particles volatility IMF volatility Kinetic Energy

Phase Changes Equilibrium trapped molecules reach a balance between evaporation & condensation

Phase Changes temp v.p. IMF v.p. Vapor Pressure pressure of vapor above a liquid at equilibrium v.p. depends on temp & IMF directly related to volatility temp temp v.p. IMF v.p.

Phase Changes Patm b.p. IMF b.p. Boiling Point temp at which v.p. of liquid equals external pressure depends on Patm & IMF Normal B.P. - b.p. at 1 atm Patm b.p. IMF b.p.

Phase Changes IMF m.p. Melting Point equal to freezing point Which has a higher m.p.? polar or nonpolar? covalent or ionic? polar ionic

Phase Changes Sublimation solid  gas v.p. of solid exceeds external pressure at or near room temperature EX: dry ice, mothballs, solid air fresheners